1. Field of the Invention
The present invention relates generally to tube quality inspection, and more particularly, to features of an ultrasonic tube inspection station which can advantageously be employed in a rapid changeover multi-diameter tube inspection system.
2. Description of the Prior Art
Because of their critical roles in fuel, control and instrumentation rods in nuclear reactors, tubes composed of zirconium and other materials must meet very stringent quality control standards. Parameters of interest are typically outside diameter, inside diameter, and wall thickness of the tube and material flaws in the tube. Ultrasonic inspection is one common method used to identify unacceptable dimensional deviations and material flaws in the tube.
These parameters of the tube are measured by ultrasonic transducers which send out ultrasound waves, pick up the echo of such waves and transform it into voltage signals which are recorded on a strip chart and visually tracked on a display, such as a cathode ray tube. These transducers, located in tanks filled with water, read the tube dimensions and flaws as a drive system feeds the tube through the tank. One conventional ultrasonic tube inspection system is disclosed in U.S. Pat. No. 3,828,609 to Furon et al. One conventional tube drive apparatus is disclosed in U.S. Pat. No. 4,735,541 to Clarence D. John, Jr. which is assigned to the assignee of the present invention.
The problem with conventional ultrasonic tube inspection systems is that in order to inspect tubes of different diameter sizes the orientation of the transducers in the tank must be changed, possibly every few hours or every week, depending on the need. The changeover time for converting the system to handle a different tube diameter size may typically take from four to eight hours.
Consequently, a need exists for improvements in ultrasonic tube inspection systems which will avoid the necessity to perform the time-consuming modifications previously required in order to inspect different sized tubes.